The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An internal combustion engine may receive intake air from a variable intake manifold (VIM). The VIM may modify a configuration of an intake tract that guides the intake air into the engine. For example, the VIM may modify a length of the intake tract, a diameter of the intake tract, a volume of the intake tract, and a number of runners that guide air into cylinders of the engine.
The VIM may include two intake tract lengths when the VIM is capable of modifying the length of the intake tract. The two intake tract lengths may accommodate different amounts of airflow into the engine. For example, a shorter intake tract may accommodate a greater amount of airflow than a longer intake tract. The VIM may include a valve that selects the length of the intake tract. An engine control module may actuate the valve to select the length of the intake tract based on engine operating conditions.